July 4, 1998
The Manchester Guardian
By Tim Radford, Science Editor
letters@guardian.co.uk

http://www.guardian.co.uk/

CANNABIS ‘IS STROKE HOPE’

Extracts of the marijuana plant could one day be routinely used to prevent brain damage after stroke, according to United States government scientists.

A team led by the British-born biologist Aidan Hampson, at the US National Institute for Mental Health, in Maryland, has discovered that two active components of cannabis - compounds called THC and cannabidiol - will each act to prevent damage to brain tissue placed in laboratory dishes.

The experiments, to be reported next week in the proceedings of the National Academy of Sciences, reveal an unexpected potential use for a drug known for centuries to have valuable medical properties. The discovery is likely to increase pressure to make marijuana and its derivatives more widely available for use on prescription.

Already, a House of Lords committee is considering the issue, the British Medical Association has reported on the drug’s virtues and the Royal Pharmacological Society is looking into the matter.

Cannabis was widely used centuries ago. There is archaeological evidence from the Stone Age of cannabis being used to ease birth pains. It is known to suppress nausea for patients on cancer chemotherapy, relieve pain and muscle spasm for multiple sclerosis sufferers, and reduce pressure in the eye for people with glaucoma.

Dr Hampson’s study has focused on cannabidiol, rather than the psychoactive chemical THC, because this substance has no side-effects. He stumbled on the finding while trying to find out why the human brain had so many "receptors" for cannabis compounds and what the receptor system was designed to do.

"There are almost as many cannabinoid receptors as there are of any major neurotransmitter, so while no one knows what it does, it seems to be pretty important."

Stroke victims suffer a blood clot which starves brain cells of glucose and oxygen, and sets off a cascade of chemical reactions which destroys cells. He found that both cannabis compounds seemed to block the destructive process. Some drugs work well in test tubes, but fail in living creatures because they do not reach the target. Cannabis compounds go straight to the brain.

The results suggest that cannabidiol could also become a treatment for other neurological disorders, such as Parkinson’s and Alzheimer’s diseases. Dr Hampson said: "We have something that passes the brain barrier easily, has low toxicity, and appears to be working in the animal trials. So I think we have a good chance."

July 4, 1998
BBC News

newsonline@bbc.co.uk

http://news.bbc.co.uk/

DOPE HOPE FOR STROKE VICTIMS

Extracts from cannabis could help reduce brain damage in stroke victims, according to new research.

American scientists say they have found that several of the chemicals in cannabis or marijuana help to prevent damage to brain tissue.

But the scientists at the US National Institute of Mental Health in Bethesda, Maryland, are not recomending smoking dope after a stroke.

The report is likely to lead to increased pressure to make marijuana and its derivatives more widely available for use on prescription.

Preventing Cell Damage

A stroke happens when a blood clot blocks one of the branches of the artery supplying the brain with blood and oxygen. If brain cells are deprived of oxygen for more than a few minutes they die.

But recent research has shown that most of the damage to the brain after a stroke is caused not directly by lack of oxygen but by the release of destructive oxidising agents which break down cells as if they were being burnt.

The Maryland team have shown that this type of damage can be largely prevented by chemicals known as cannabinoids which are found in marijuana.

Dr Aidan Hampson of the NIMH said: "We have found that cannaboids are very powerful anti-oxidants. In fact they appear to be more powerful than vitamin C or vitamin E."

What is not clear is whether smoking marijuana will release enough of the cannaboids to do any good.

Instead scientists hope to use synthetic cannabinoids to reduce brain damage after strokes, and possibly to slow up the progress of Alzheimers disease and Parkinsons disease as well.